On Tue, 22 Apr 2025 at 12:30, Tanmay Shah <tanmay.s...@amd.com> wrote:
>
>
>
> On 4/22/25 12:49 PM, Mathieu Poirier wrote:
> > On Tue, 22 Apr 2025 at 10:10, Tanmay Shah <tanmay.s...@amd.com> wrote:
> >>
> >>
> >>
> >> On 4/22/25 10:59 AM, Mathieu Poirier wrote:
> >>> Good morning,
> >>>
> >>> On Mon, Apr 14, 2025 at 11:46:01AM -0700, Tanmay Shah wrote:
> >>>> Powering off RPU using force_pwrdwn call results in system failure
> >>>> if there are multiple users of that RPU node. Better mechanism is to use
> >>>> request_node and release_node EEMI calls. With use of these EEMI calls,
> >>>> platform management controller will take-care of powering off RPU
> >>>> when there is no user.
> >>>>
> >>>> Signed-off-by: Tanmay Shah <tanmay.s...@amd.com>
> >>>> ---
> >>>> drivers/remoteproc/xlnx_r5_remoteproc.c | 29 ++++++++++++++++++++++++-
> >>>> 1 file changed, 28 insertions(+), 1 deletion(-)
> >>>>
> >>>> diff --git a/drivers/remoteproc/xlnx_r5_remoteproc.c
> >>>> b/drivers/remoteproc/xlnx_r5_remoteproc.c
> >>>> index 5aeedeaf3c41..3597359c0fc8 100644
> >>>> --- a/drivers/remoteproc/xlnx_r5_remoteproc.c
> >>>> +++ b/drivers/remoteproc/xlnx_r5_remoteproc.c
> >>>> @@ -380,6 +380,18 @@ static int zynqmp_r5_rproc_start(struct rproc
> >>>> *rproc)
> >>>> dev_dbg(r5_core->dev, "RPU boot addr 0x%llx from %s.",
> >>>> rproc->bootaddr,
> >>>> bootmem == PM_RPU_BOOTMEM_HIVEC ? "OCM" : "TCM");
> >>>>
> >>>> + /* Request node before starting RPU core if new version of API is
> >>>> supported */
> >>>> + if (zynqmp_pm_feature(PM_REQUEST_NODE) > 1) {
> >>>> + ret = zynqmp_pm_request_node(r5_core->pm_domain_id,
> >>>> + ZYNQMP_PM_CAPABILITY_ACCESS, 0,
> >>>> +
> >>>> ZYNQMP_PM_REQUEST_ACK_BLOCKING);
> >>>> + if (ret < 0) {
> >>>> + dev_err(r5_core->dev, "failed to request 0x%x",
> >>>> + r5_core->pm_domain_id);
> >>>> + return ret;
> >>>> + }
> >>>> + }
> >>>> +
> >>>> ret = zynqmp_pm_request_wake(r5_core->pm_domain_id, 1,
> >>>> bootmem, ZYNQMP_PM_REQUEST_ACK_NO);
> >>>> if (ret)
> >>>> @@ -401,10 +413,25 @@ static int zynqmp_r5_rproc_stop(struct rproc
> >>>> *rproc)
> >>>> struct zynqmp_r5_core *r5_core = rproc->priv;
> >>>> int ret;
> >>>>
> >>>> + /* Use release node API to stop core if new version of API is
> >>>> supported */
> >>>> + if (zynqmp_pm_feature(PM_RELEASE_NODE) > 1) {
> >>>> + ret = zynqmp_pm_release_node(r5_core->pm_domain_id);
> >>>> + if (ret)
> >>>> + dev_err(r5_core->dev, "failed to stop remoteproc
> >>>> RPU %d\n", ret);
> >>>> + return ret;
> >>>> + }
> >>>> +
> >>>> + if (zynqmp_pm_feature(PM_FORCE_POWERDOWN) < 1) {
> >>>> + dev_dbg(r5_core->dev, "EEMI interface %d not supported\n",
> >>>> + PM_FORCE_POWERDOWN);
> >>>> + return -EOPNOTSUPP;
> >>>> + }
> >>>
> >>> Here I have to guess, because it is not documented, that it is the check
> >>> to see
> >>> if zynqmp_pm_force_pwrdwn() is available. I'm not sure why it is needed
> >>> because
> >>> zynqmp_pm_force_pwrdwn() returns and error code.
> >>>
> >> Hello,
> >>
> >> Thanks for reviews. Yes you are correct. Actually instead, the check
> >> should be for version 1 of PM_FORCE_POWER_DOWN. If version 1 is
> >> supported, only then execute the call otherwise print the error.
> >> Hence, the check should be something like:
> >>
> >> if (zynqmp_pm_feature(PM_FORCE_POWERDOWN) != 1) {
> >> error out.
> >> }
> >>
> >
> > The above still doesn't answer my question, i.e _why_ is a check
> > needed when zynqmp_pm_force_pwrdwn() returns an error code? To me, if
> > something happens in zynqmp_pm_force_pwrdwn() then an error code is
> > reported and the current implementation is able to deal with it.
> >
>
> PM_FORCE_POWERDOWN will print redundant error messages from firmware if
> called for feature that is not supported. By doing above version check,
> we are avoiding those unnecessary error/warning messages. Other than
> that, you are correct we don't need to do version check as
> PM_FORCE_POWERDOWN will send respective error code and we will fail
> here. But version check helps to differentiate between actual error log
> from firmware when call is expected to work.
>
That is the kind of information that would be useful as comments in
the code. Otherwise there is simply no way to tell...
> >> I will fix and add comment as well.
> >>
> >>> Thanks,
> >>> Mathieu
> >>>
> >>>> +
> >>>> + /* maintain force pwr down for backward compatibility */
> >>>> ret = zynqmp_pm_force_pwrdwn(r5_core->pm_domain_id,
> >>>> ZYNQMP_PM_REQUEST_ACK_BLOCKING);
> >>>> if (ret)
> >>>> - dev_err(r5_core->dev, "failed to stop remoteproc RPU %d\n",
> >>>> ret);
> >>>> + dev_err(r5_core->dev, "core force power down failed\n");
> >>>>
> >>>> return ret;
> >>>> }
> >>>>
> >>>> base-commit: 8532691d0a85ab2a826808207e904f7d62a9d804
> >>>> --
> >>>> 2.34.1
> >>>>
> >>
>
